The Tunograph is believed to be the first CRT based tuning indicator. It was made by STC under the Micromesh name and then later as a Brimar product.
The balloon envelope is 48 mm in diameter, and excluding the B5 base pins is 135 mm tall.
Reference: Datasheet. Type Tunograph was first introduced in 1933.
Absolute Maximum Operating Conditions¶
Updated August 30, 2018. shape:balloon construction:pinch type:tuning.indicator age:1930.1940 base:b5 pins:5 pin:1.a pin:2.p pin:3.f pin:4.f